While making a presentation, a fire marshal asked me whether the code requires visible signals to be deactivated when the audible signals are silenced. I referred him to Section 10.12.2 of the National Fire Alarm and Signaling Code, which states, “When an occupant notification alarm signal deactivation means is actuated, both audible and visible notification appliances shall be simultaneously deactivated.” So, the obvious answer was yes, but the discussion did not end there.

He demanded to know why the technical committee required that (the change was made in 2010!). He was adamant that the visible signal should remain operating when the audible signals are silenced to let the building occupants know there is still an active alarm being investigated. He said the main reason his department follows this procedure is that the audible signals continually sounding interfere with firefighters’ abilities to use their radios.

Fortunately, there is something in the annex to accommodate his request. The technical committee provided additional guidance in Annex A that states in Section A.10.12.2, “Where it is desired to deactivate the notification appliances for fire service operations inside the building and signal occupants that an alarm is still present, it is recommended that a separate non­silenceable notification zone be provided on the exterior of the building. The audible and visual notification appliances at the building entrances could serve as a warning to prevent occupant reentry.” What is not stated is that signs explaining what these outside notification appliances mean should be added.

Imagine my surprise when I returned from the presentation and had another fire marshal contact me with a similar question! I now had time to more thoroughly answer the question and continue the dialogue.

History first

First, a little history. Silencing the audible signals while leaving the strobes flashing crept into use in the 1980s. At the time, only one product could perform in such a way. The manufacturer sold this idea exactly as described above. Meanwhile, specifications often called for this manufacturer’s equipment only, so competitors were not factored in to project bids. 

Then, over time, it became a tradition without any substantiation in the code. As I understand, in most fire response situations, first responders expect that all occupants will be evacuating (or already out) as the responders arrive. Once the fire department is on-site, they will maintain control over the building and not allow anyone to enter until it is clear.

No occupant training programs or code language exists that states that flashing strobes without audible signals sounding in the building means the fire department is investigating and occupants cannot re-­enter. Strobes only exist to provide notification for deaf and hard of hearing occupants.

Big problems abound

The confusion caused by that limited use seems to be why this change was made to NFPA 72 in 2010. Continuing in this manner may lead people in the building who are not first responders to believe that as soon as an alarm sounds, they can silence the audible signals while they decide if it is a real alarm or not. This is not a safe way to treat an alarm signal and not something we would want to encourage. Unfortunately, using strobe lights in this way only helps to emphasize that when the alarm signal sounds, occupants can assume it is false until they get a second cue from the first responders.

I believe this could cause more people to be potentially trapped in a building where there is a real fire and force first responders to deal with rescues before fighting the fire.

Is this a tradition really born out of false alarm issues? False alarms happen, I know, but it would be more beneficial to look at other methods to avoid them, such as stricter enforcement of testing and maintenance.

It may make sense to use the suggestion in Annex A to satisfy the fire service’s needs. 

Of course, we all agree that continually sounding audible signals interfere with the radio traffic. However, continuing to encourage the occupants of a building to not leave by first silencing the audible signals and leaving the strobes flashing does not appear to be the safest method to follow. The practice also creates a serious conflict with the ADA and may confuse those who are deaf or hard of hearing about the alarm condition.

If someone asks you to program your system like this, ensure you point out the conflict with the code and the option suggested in the annex. But do not program your system to be noncompliant with the code.

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